This invention relates to the art of gearshifting mechanisms and, more particularly, to improvements in manually operable gearshift mechanisms for shifting gears in a vehicle transmission.
It is well known that vehicle transmissions provide a plurality of selectable gear combinations, and it is likewise known that certain transmissions provide for the gears to be shifted from one combination to another through appropriate positioning of a pair of gearshift operators associated with the transmission and which are displaceable relative to one another and to the transmission housing by generally lineally displaceable gearshift actuators such as cables. The actuating cables are lineally displaced through the vehicle operator's manipulation of a manual gearshift mechanism in the vehicle and which mechanism includes a pivotal gear selector member having a plurality of positions corresponding to available gear combinations in the transmission. Pivotal displacement of the gear selector relative to a support therefor is translated to linear displacements of the cables and, in connection with the operation of an automobile for example, the gear combinations achieved through such positioning include a neutral gear, a reverse gear, and a plurality of forward drive gear ratios.
Manually operable gearshift mechanisms heretofore provided for achieving such transmission gear changes, while effective for the intended gearshifting purposes, are structurally complex and thus both excessively heavy and undesirably expensive to produce. More particularly in this respect, prior constructions have required the use of an excessive number of interengaging component parts, many of which require close tolerances and finished surfaces, thus involving time consuming and expensive machining operations and assembly operations. Moreover, such constructions are undesirably heavy as a result of the number of component parts and the size and weight thereof and, additionally, are undesirably large with respect to the outside dimensions thereof. Furthermore, structurally complex arrangements for translating motion within the gearshift mechanisms and for providing lockout arrangements with respect to unintentional shifting of the transmission into reverse gear, have added to the cost and weight of the mechanisms while, at the same time, taking away from the efficiency and stability of the mechanism with respect to the operation thereof.
Still further, the multiple position shifting of the gearshift selector in connection with the relative positioning of a pair of transmission gear actuators has heretofore required the lateral displacement within the support of one of the gear actuators relative to a linear path of reciprocating displacement therefor. Such lateral displacement is followed by longitudinal displacement of the actuator and, thus, bending thereof at the point where the actuator passes through the support toward the vehicle transmission. This bending of the actuator during longitudinal displacement thereof is undesirable in that it promotes wear of the actuator and the portion of the support slidably interengaged thereby. More importantly, from the standpoint of the vehicle operator, is the fact that such bending necessitates the use of varying degrees of force to displace the actuator depending on the extent of lateral displacement of the latter from its linear path. This, of course, is reflected in the "feel" of the shifting operation to the vehicle operator and results in a different feel for the various gearshifting movements of the gearshift selector.